Integrated circuits are used in many portable electronic products, such as cell phones, portable computers, voice recorders, etc., as well as in many larger electronic systems, such as cars, planes, industrial control systems, etc. Integrated circuits may include a combination of active devices, passive devices and their interconnections.
Electrical interconnections for current 65 nm and 45 nm integrated circuits commonly employ silicide or salicide interfaces to reduce their electrical contact resistance. Generally, these silicide or salicide interfaces are formed via a rapid thermal annealing (RTA) process, which utilizes transient lamp heating to create a uniform temperature distribution in the microstructures across the wafer. Unfortunately, RTA processes generally only allow for the adjustment of horizontal temperature profiles across a wafer and they are unable to control the temperature profile in the vertical direction on the wafers. This imprecise temperature control causes undesirable refractory metal diffusion effects that form defective metal silicides. Typical metal silicide defects include spiking, piping, and refractory metal or metal silicide residue left on top of a spacer, which can lead to a poly-contact short.
In the latest wafer processing technology, laser annealing techniques have been developed to lessen the occurrence of undesirable refractory metal diffusion. For example, pulsed laser techniques have been employed because of their improved ability to control the thermal diffusion length of dopants, making it a desirable tool for shallow junction processes. However, conventional laser annealing of wafers is typically carried out from the front-side of the wafer, and the metal layer blocks the laser irradiation, thereby preventing direct heating at a metal/silicon interface. As a result, it is difficult to control the temperature profile at the metal/silicon interface during a laser silicidation process.
Thus, a need still remains for a reliable integrated circuit system and method of fabrication, wherein the integrated circuit system exhibits reduced defective metal silicide occurrences and/or an improved temperature profile at the metal/silicon interface. In view of the ever-increasing commercial competitive pressures, increasing consumer expectations, and diminishing opportunities for meaningful product differentiation in the marketplace, it is increasingly critical that answers be found to these problems. Moreover, the ever-increasing need to save costs, improve efficiencies, and meet such competitive pressures adds even greater urgency to the critical necessity that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.